Impact drivers excel at fastening screws thanks to worthy torque and speed. But which one should you buy? We rounded up 9 li-ion impact drivers and put them to the test. Here are the results.

Impact Driver Comparison Test

Impact Driver Comparison Test

There's no telling nowadays what people build. Decks, docks, treehouses, pressure-treated retaining walls, sheds, fences and firewood racks are projects our readers have asked about recently. This work calls for lots of fasteners, especially lag screws. Only one tool combines rotational speed and blows per minute in a way that makes it excel at driving these big screws: the impact driver. It's faster and more consistent than a drill driver and transfers less reaction torque to you. We gathered nine li-ion impact drivers, and a thousand screws later, here's what we found.